From tomorrow (18 April), work will begin to shore up a collapsing quarry face in the Vale.
Building the barrier at L'Epine will allow the minor lane next to it to reopen.
The road was closed without warning last June because it was considered dangerous.
The Vale Constables were told by Guernsey Water that the barrier, or 'bund' is a sizeable structure.
The stone will be brought in by tractor, so parking in the access road will be suspended on weekdays.


Guernsey gets behind community café after online appeal
Guernsey Waste warn of the fire hazard of disposable vapes
No rush to ban social media for the under-16s in Guernsey
Guernsey businesses encouraged to use the daily St Malo ferry for European imports
Guernsey's airline to drop its European holiday routes
A total ban on disposable vapes in Guernsey and Jersey is poised to take full effect
Guernsey's Air Display to remain an early evening event
Disgraced Guernsey politician and pastor jailed for 9 years